The coin dates to the period of the Commonwealth of England, 1649 - 1660. Previously, the image of the king had been used to show that the coinage was backed by the government, but after the execution of King Charles I, a new, kingless coin had to be designed.
Henry III coin with name of Moneyer William. The making (minting) of coins was done by companies. These 'moneyers' as they were known paid a fee for the privilege of making the coins. Their names appear on many of the earlier coins, like this one, which has the name of Moneyer William.